Snap action switches with improved operating mechanism

ABSTRACT

The electrical switch includes a casing having a base carrying fixed contacts, and a movable contact assembly slidable relative to the base, the movable contact of the assembly being engageable with the fixed contacts. Detent means are provided on the movable contact assembly and the casing for locating the movable contact relative to the base in any one of a number of operative positions, and an operating member is provided for moving the movable contact assembly. Resilient means acts between the movable contact assembly and the operating member, and the operating member is provided with cam means for releasing said detent means during movement of the operating member. During movement of the operating member as the detent means is released, said resilient means is stressed so that when the detent means releases the resilient means moves the movable contact assembly relative to the fixed contacts.

United States Patent [72] Inventor Keith Lewis Burnley, England [21 Appl. No. 797,880 [22] Filed Feb. 10, 1969 [45] Patented Mar. 2, 1971 [73] Assignee Joseph Lucas (Industries) Limited Birmingham, England [32] Priority Feb. 16, 1968 [3 3] Great Britain [31] 7640/68 [54] SNAP ACTION SWITCHES WITH IMPROVED OPERATING MECHANISM 2 Claims, 6 Drawing Figs.

[ 5 2] US. Cl 200/68, 200/ 77 [51] lnt.Cl .l-l0lh 15/18 [50] Field otSearch 200/68, 70, 76, 78, 77

[S 6] References Cited UNITED STATES PATENTS 3,053,950 9/1962 Dobes 200/78 L L'J-I 3,333,074 7/l967 Hults 3,339,032 8/1967 Hults ABSTRACT: The electrical switch includes a casing having a base carrying fixed contacts, and a movable contact assembly slidable relative to the base, the movable contact of the assembly being engageable with the fixed contacts. Detent means are provided on the movable contact assembly and the casing for locating the movable contact relative to the base in any one of a number of operative positions, and an operating member is provided for moving the movable contact assembly. Resilient means acts between the movable contact assembly and the operating member, and the operating member is provided with cam means for releasing said detent means during movement of the operating member. During movement of the operating member as the detent means is released, said resilient means is stressed so that when the detent means releases the resilient means moves the movable contact assembly relative to the fixed contacts.

PATENTEB mik 2197! SHEET 1 BF 2 PATENTEDQAR 2197: 3567.883

SHEET 2 [1F 2 INVENTOE WW mwms SNAP ACTION SWITCHES WITH IMPROVED OPERATING MECHANISM This invention relates to electrical switches.

An electrical swit'ch according to the invention comprises, a hollow casing including a base, a plurality of fixed contacts carried by said base, a movable contact engageable with said fixed contacts and mounted for sliding movements relative to said base, detent means acting between the casing and said movable contact for locating the movable contact relative to said base in the operating positions of the switch, an operating member pivotally engaged with the casing, means on the operating member for releasing said detent means during movement of said operating member, and resilient means acting between the operating member and the movable contact, said resilient means being stressed during movement of the operating member relative to the casing and serving to move said movable contact relative to said base when said detent means is released.

One example of the invention is illustrated in the accompanying drawings wherein FIG. 1 is a sectional view of an electrical switch, FIG. 2 is a sectional view on the line 22 in FIG. 1, FIG. 3 is a sectional view of the operating member of the switch shown in FIG. 1, FIG. 4 is a sectional view on the line 4-4 in FIG. 3, FIG. 5 is asectional view on the line 5-5 in FIG. 2, with parts thereof omitted for clarity, and FIG. 6 is a sectional view of a contact carrier of the switch shown in FIG. 1.

Referring to the drawings, the switch includes a hollow moulded synthetic resin casing 11 which is closed at one end by a contact board 12 engaged as a snap fit with the casing 11. The end walls of the casing 11 are provided with respective resilient catches 13 through which the switch may be engaged as a snap fit in a correspondingly shaped hole in a panel, for instance the facia panel of a road vehicle. The contact board 12 constitutes the base of the casing 11 and carries a plurality of fixed contacts 14 which project upwardly into the casing 11. The contacts 14 are electrically connected to terminals 15 positioned on the exterior of the contact board 12.

Slidably mounted within the casing 11 for movement in a direction parallel with the contact board 12 is a moulded synthetic resin contact carrier 16. A movable bridging contact 17 is carried by the carrier 16 and is urged into contact with the contacts 14 by springs 18 acting between the carrier 16 and the bridging contact 17. The opposite sidewalls 11a of the casing 11 are each formed with an inwardly directed arcuate shoulder 19 and each of the shoulders 19 is formed with three depressions 21a, 21b, 210 respectively. The carrier 16 is formed with a transverse channel 22, which is enlarged adjacent the center of the carrier 16, and a steel roller 23, having a pair of axially aligned end portions 24, which are joined by a center spherical portion 25, is engaged in the channel 22.

Upstanding from the walls 11a of the casing are a pair of lugs 26 and pivotally engaged with the lugs 26 is a moulded synthetic resin operating member 27 (FIG. 3). Integral with the member 27 are a pair of identical arms 28, which are spaced transversely from one another across the member 27. The arms 28 extend downwardly from the operating member 27 into the casing 11 and lie adjacent opposite sides of a raised portion of the carrier 16. The arms 28 of the member 27 are each formed with a window 29, the base of which is generally V-shaped, having a pair of inclined edges 31. The ends 24 of the roller 23 extend through the window 29 into engagement with the depressions 210 or 21b or 21c, in the walls 11a of the casing. The ends 24 of the roller 23 are normally engaged with the apices of the bases of the windows 29 in the arms 28, and a spring 32 acts between the member 27 and the spherical portion of the roller 23 to urge the roller 23 downwardly into engagement with the depressions and the apices of the windows 29. The operating member 27 further includes two pairs of integral fingers 34, 35, the pairs of fingers 34, 35 being spaced from one another longitudinally of the member 27 while the fingers of each pair are spaced from one another transversely of the member 27. The pairs of fingers 34, 35 are resilient, and engage with respective shoulders at the opposite ends of the carrier 16. The operationof the switch is as follows. As shown the switch is in a first operative position, wherein the bridging contacts 17 engage a first set of contacts (not shown) on the contact board 12, to complete a first electrical circuit therebetween. Moreover, in the first operative position of the switch the ends 24 of the roller 23 are engaged with the depressions 21b in the sidewalls 11a of the casing to maintain the switch in the first operative position. When it is desired to move the switch to its second operative position, that is to say, to move the carrier 16 and contact 17 to the left as shown in the drawings, the operating member 27 is manually pivoted in a clockwise direction. Since the member 16 is held in its first position by engagements of the ends 24 of the roller 23 in the depressions 21b, initial clockwise movement of the operating member 27 causes flexure of the fingers 35. Moreover, the initial clockwise movement of the member 27 causes the roller 23 to ride up one of the inclined edges 31 of each of the bases of the windows 29 in the arms 28of the member 27. The roller 23 is moved upwardly, against the action of the spring 33 until the ends 24 of the roller 23 are lifted out of the depressions 21b in the walls of the casing 11. When the ends 24 of the roller 23 clear the depression 21b in the walls 11a of the casing 11 the carrier 16 is no longer held against sliding movement relative to the contact board 12 and the carrier 16 is moved to the left as shown in the drawing by the resilience of the fingers 35. As the carrier 16 moves to the left, the roller 23 is carried to the left with the carrier 16 and its ends 24 engage wall 21b adjacent the depressions 21a to limit the movement of the carrier 16. When the ends 24 of the roller 23 engage the walls 21b the movement of the carrier 16 is arrested and the roller is urged downwardly by the spring 33 to engage the ends 24 of the roller 23 in the depressions 21a, thereby locating the switch in its second operative position. The bridging contact 17 is now in a position completing the circuit between a second set of contacts on the contact board 12. Moreover, since the operating member 27 was moved in a clockwise direction the arms 28 thereof will have moved generally to the left and the ends 24 of the roller 23 will again engage the apices of the bases of the windows 29.

The action of the switch when being moved from its second position back to its first position, or when being moved from its first position, to its third position, is similar to that described above, with the exception that the operating member 27 is moved in a counterclockwise direction, the carrier 16 and the bridging contact 17 moving accordingly to the right as shown in the drawings.

It will be appreciated that the components of the switch described above could be modified in such a manner that the roller 23 is moved downwardly against the action of a spring, to clear downwardly presented depressions in the walls 110 of the casing 11. Moreover it will be further appreciated that other forms of contacts to those shown could be carried by the board 12. lclaim: 1. An electrical switch comprising: a hollow casing including a base; a plurality of fixed contacts carried by said base; a movable contact engageable with said fixed contacts; means mounting said movable contact for sliding movement relative to said base; I

detent means acting between the casing and said movable contact for locating the movable contact relative to the base in the operating positions of the switch;

an operating member;

means pivotally mounting the operating member on the casmeans on the operating member for releasing said detent means during movement of said operating member; and resilient means integral with the operating member, said resilient means engaging said movable contact and being stressed during movement of the operating member relative to the casing, prior to said movement causing release of said detent means, said stressed resilient means then serving to move said movable contact relative to said base when said detent means is released by said movement of the'operating member.

2. A switch as claimed in claim 1 wherein said detent means includes:

a part carried by said movable contact;

a detent form on the casing;

resilient means urging said part into engagement with said detent form, so as to retain said movable contact in posi- 

1. An electrical switch comprising: a hollow casing including a base; a plurality of fixed contacts carried by said base; a movable contact engageable with said fixed contacts; means mounting said movable contact for sliding movement relative to said base; detent means acting between the casing and said movable contact for locating the movable contact relative to the base in the operating positions of the switch; an operating member; means pivotally mounting the operating member on the casing; means on the operating member for releasing said detent means during movement of said operating member; and resilient means integral with the operating member, said resilient means engaging said movable contact and being stressed during movement of the operating member relative to the casing, prior to said movement causing release of said detent means, said stressed resilient means then serving to move said movable contact relative to said base when said detent means is released by said movement of the operating member.
 2. A switch as claimed in claim 1 wherein said detent means includes: a part carried by said movable contact; a detent form on the casing; resilient means urging said part into engagement with said detent form, so as to retain said movable contact in position relative to the casing; and the switch further including a cam form on a part integral with the operating member, said cam form being engageable with said part during pivoting movement of the operating member relative to the casing, so that during said pivoting movement said cam form can move said part as an engagement with said detent form thereby releasing the movable contact to permit sliding movement of the movable contact relative to the casing. 